Rotary grate for boiler and heating plants



April 21, 1931.

C. J. SANDOE ROTARY GRATE FOR BOILER AND HEATING PLANTS Filed April 2. 1929 2 Sheets-Sheet l /6 Tm 2 I 1 um 1 13 5 H i 34 ll" l 1 4 flarexzaeJJahdae 'l lllillllllllll' April 21, 1931- c. J. SANDOE 1,801,694

ROTARY GRATE FOR BOILER AND HEATING PLANTS Filed April 2, 1929 2 Sheets-Sheet 2 ix- W A M" I i \I/ l l 5i I K; '7

. I m i" l l .4. I y l \6' 1 w 4 a T v 3 ,75 6 57 I" IIIHHI mflunhg Q; 16 /7 W a. /7

' t 6 a 6 w 32 Mu g: 3, 0 2 /6-30 Patented Apr. 21, 19 31 CLARENCE J'. SLNDOE, 01 8'1. LOUIS, MISSOURI ROTARY GRA'IE FOR BOILER AND HEATING- PLANTS Application filed April 2, 1929. Serial No. 351,909.

like numerals designate like parts in all the views,

Figure 1 is a front elevational view of filirnlace to which this invention has been app 1e V Figure 2 is a side elevational view of a portion of the furnace above shown with parts broken away to more clearly illustrate the invention;

Figure 3 is a fragmentary detail in section illustrating the actuating mechanism of the rotary grate; V

Figure 4 is a semidiagrammatic vertical sectional view of the furnace shown in Figure 1 and the invention applied thereto;

Figure 5 is a horizontal sectional view of the parts shown in, Figure 4 and taken as on the line 5-5 thereof, looking in the direction of the arrows; and

Figure 6 is a vertical sectional detail view of the deflector used in connection with this invention.

In order that this invention may be the better understood it is said that in heretofore known furnace constructions. the grate has been incapable of insuring a steady, even and complete combustion of the coal or coke, with the result that there exists a cold or dead area extending upwards circumferentially of the grate so that the live or active portion of the bed of coals is of reduced area and generally U shaped. In other words the prior constructions cause an accumulation of unburned, half-burned, or completely burned fuel around the outer ed portion of the grate next to the wall 0 the fire-pot, and while in some stoves'and furnaces this may be broken up and removed by the aid of a poker yet the results have been unsatisfactory due to the fact that the poker cannot effectively function at all circumferential portions of the grate, as will be readily understood. This invention on the other hand contemplates a construction which will periodically free the grate, at all points, of the aforementioned accumulation of dead or inactive fuel, thus keeping the grate open and making possible a combustion area of greater extent, and a hotter bed of coals, than here tofore was possible with a grate of the same size. Further, with this invention in use, it is possible to burn varying grades of fuel because the draft is maintained practically through the entire grate area. Also, the

completely burned residue and the unburned or half-coked lumps of fuel are automatically fed by the rotation of the grate to a central portion of said grate for complete combustion and dumping.

In the drawings, 1 indicates the base of a furnace, 2 the grate supporting section, 3 the drum enclosing the combustion chamber, 4 the fuel inlet provided with an automatic or hand operated screw conveyor 5, 6 the flue for the products of combustion, and 7 the top or head of the furnace. The grate supporting section carries the ash pit which is preferably formed with opposed inclines 10 and 11 downwardly converging into a central transverse circular trough 12 into which fits a screw 13 having means, such as a squared end portion 14 to which a handle may be fitted, for rotating said screw.

Around the sides of the grate section is disposed at spaced intervals a plurality of lugs 15 whose upper extremities lie in a horizontal plane for the purpose of supporting.- the circular grate generally indicated by the. numeral 16. The grate comprises a fiat per tion whose peripheral edge is provided with circumferentially disposed ratchet teeth 17, see Figure 3, adapted to be engaged by a pawl 18 working through a slot 19 in the wall of the grate section 2. That is to say, there is provided exteriorly of the furnace on the grate section, a box 20 having a laterally, extending chamber 21 within which is disposed a spring 22 adapted to press against the arm 23 at the end of which is carried the 'pawl 18, for the urpose of causing positive engagement of t e teeth 17 by said pawl. The arm 23 extends out'of the box 20 and is connected by suitable links and pivots to an operating lever 25 preferably pivoted at its lower end as at 26 to a bracket 27 formed as an extension of the base 1 of the furnace all as will be clearly understood from the drawings. It will thus be evident that as the lever 25 is actuated, the pawl 18 will successively engage the teeth 17 formed on the edge of the grate, causing a rotation of the latter.

The center portion of the grate is depressed or dished as indicated at 30 to form an inverted cone, and the actual central portion of this cone is omitted to provide a circular opening 31 within which fits the circular apertured plate 32 secured'to a rod 33 whose end is squared as at 34 to receive a handle by means of which the circular plate 32 may be rotated to cause a dumping of the ma terial on the grate. The material so dumped .will fall upon the inclines 10 or 11 and be ultimately moved to the screw conveyor 13 for expulsion from the furnace through the duct 35. The rod 33 is suitably supported by brackets as clearly indicated in Figure 2. The fiat portion as well as the conical portion of the grate is apertured in any suitable manner to provide means for air passing upwardly therethrough to create the draft for the fire.

Immediately above the grate and secured to the inner wall of the grate section as by the lugs 37, is a deflector which extends arcuately as indicated at 38 toward the conical portion of the grate. In other words, there is provided a member which extends into the fire pot at an angle to the direction of rotation of the grate in such manner'that it will intercept the material on the grate and cause a movement thereof to the central conical section of the grate. By this construction it is therefore possible to clean the surface of the grate periodically and automatically as the grate is rotated; thus preventing a superaccumulation of com letely burned, partly burned, or unburned e1, on the grate at the circumferential edge portion thereof. Thus any material which is not completely burned will be moved into an area of the 'rate where better draft facilities occur with resultant complete combustion, and the material which is completely burned will be forced by the deflector into the central area of the grate where the dumping section is located. The fuel inlet 4 is locatedat a point in the wall of the furnace so that the fuel will be deposited at a point on the rate behind the deflector 38, see Figure 5. That is to say the fuel will be deposited at a point on the grate which has just passed beneath the deflector, so that said fuel will be enabled to travel substantially all the way around the furnace before it will be acted upon by the deflector.

Of course there will be considerable depth to the bed of coals upon the grate so that the fresh fuel will be deposited in the furnace well above the deflector, but the deflector is made of such a vertical dimension that it will positively affect the material on the upper surface of the grate which has or should have been completely combusted b the time it reaches the deflector, without a ecting the burning of unconsumed fuel material in the fire pot. The are of the deflector 38 is such as to cause an easy movement or scra ing of the material on the upper surface 0 the grate to a portion central thereof.

The grate may be rotated step by step by the hand operated lever 25 at stated intervals of time, or the grate may be connected through the pawl 18 to an automatic actuated mechanism all within the scope of this invention since this forms no part of the real invention. In other words, any means for rotating the grate may be employed.

It is obvious that those skilled in the art may vary the details of construction and combinations of parts without departing from the spirit of the invention and therefore it is not desired to be limited to the foregoing construction except as may be demanded by the claims. 4

What is claimed is z 1. In a device of the character described the combination of a grate comprising a flat circumferential portion and a conically depressed central portion having a tiltable bottom; means to move said grate step by step including areciprocable member engageable with projections formed on said grate; and means carried by the wall of the furnace and extending across the flat portion of said grate to move the fuel material thereon into said conical portion and on to said bottom when said grate is actuated.

2. In a device of the character described the combination of a grate comprising a circular casting having a central depression and a tiltabie bottom, means to rotate said grate and means tangentially reciprocahle with respect to said grate and including a pawl and ratchet; and means to move material into said depression and on to said bottom upon rotation of said grate. v

3. A grate mechanism including a furnace wall, and a grate provided in its edge with radially extending ratchet teeth by which the grate may be moved, and smooth ortions, said portions extending outwardly a ove and below and protectively adjacent said teeth, the teeth registeringwith an opening in the furnace wall and the smooth portions slidingly contacting with the surface of said wall.

4. A grate mechanism including a furnace wall, and a grate having a channel formed in its periphery, the flanges of said channel terminating in smooth edges, the web of said channel having radially extending members by which the grate may be moved, the members registering with an o ening in the fur 5 nace wall and the smooth e ges slidingly contacting with the surface of said wall.

5. A grate mechanism including a furnace wall, and a grate provided in its edge with I radially extending sunken ratchet teeth and 1 smooth portions extending outwardly adjacent said teeth, the teeth by which the grate may be moved registering with an opening in the furnace wall and the smooth portions slidingly contacting with the surface of said wall to protect said teeth.

6. A grate mechanism including a furnace wall, and a grate structure comprising two. rotatable grates one fitting within the other, the larger provided in its edge with radially extending sunken ratchet teeth by which the grate may be moved and teeth protectin portions, said portions having outer smoot surfaces, the teeth registering with an opening in the furnace wall and the smooth surfaces slidingly contacting with the surface of said wall, the smaller grate rotatable transversely to the plane of rotation of the larger grate.

7. A grate structure including a furnace wall and comprising two rotatable grates one fitting within the other, the larger provided in its edge with radially extending teeth by which the grate may be moved and teeth protecting portions, said portions having outer smooth surfaces, the teeth registering with an I opening in the furnace wall and the smooth surfaces slidingly contacting with the surface of said wall, the smaller grate rotatable transversely to the plane of rotation of the larger grate, each of said grates mounted independently of the other.

, 8. A grate mechanism consisting of two rotary grates normally dis osed 1n arallel planes and one fitting wit in the ot er, the larger grate provided in its edge with ratchet teeth and smooth portions the teeth registering with an opening in the furnace wall and the smooth portions slidingly contacting the inner surface of said wall, a longitudinally reciprocable member constituting a pawl having an end passing through the furnace wall opening and engageable with said teeth for rotating said larger grate said member yieldably confined in a transverse direction in a housing secured to said wall permitting backward movement of the pawl over said teeth without imparting rotation to said larger grate, the smaller grate supported free of the" larger grate and rotatable substantially about one of its diameters as an axis, and a deflector 0 secured to and extending inwardly from the furnace wall substantially to the smaller grate to move fuel material thereonto from the larger grate when the latter is rotated.

In testimony whereof I afiix my signature.

CLARENCE J. SANDOE. 

